Process of making paper containing quaternary ammonium starch ethers containing anionic covalent phosphorus and paper made therefrom

ABSTRACT

STARCH SUITABLE FOR USE AS BEATER ADDITIVE HAVING A QUATERNARY AMONIUM ETHER D.S. OF 0.005 TO 1.5 AND ABOUT 0.01 TO 1 COVALENT ANIONIC PHOSPHATE OR ETHER PHOSPHONATE GROUPS PER QUATERNARY AMMONIUM ETHER GROUP, PROCESS OF MAKING PAPER WITH AND PAPER MADE THEREFROM.

United States Patent US. Cl. 162175 9 Claims ABSTRACT OF THE DISCLOSURE Starch suitable for use as beater additive having a quaternary amonium ether D8. of 0.005 to 1.5 and about 0.01 to 1 covalent anionic phosphate or ether phosphonate groups per quaternary ammonium ether group, process of making paper with and paper made therefrom.

DISCLOSURE OF THE INVENTION This invention relates to quaternary ammonium ether starch phosphates and phosphonates and their use as beater additives. More particularly, this invention relates to quaternary amonium ether corn starch phosphates and phosphonates and their use as beater additives.

In the manufacture of paper webs, pulp, waste paper, or both are vfirst dispersed in water under conditions to minimize any changes in the cellulose fibers. Then the dispersed pulp is subjected to a process of beating or refining in which the pulp is circulated between relatively rotating members that may have bars or knives. Fiber surface and flexibility are increased and fiber length is decreased. Water is taken up by the fibers, and their physical structure is mechanically loosened. There is a decrease in pulp freeness.

Particularly for printing, for ledger and for records paper, it has become necessary to add fillers or pigments to the stock to impart opacity. Paper that is thinner and lighter in weight is increasingly demanded to reduce the weight of printed material that must be shipped and mailed. To impart opacity to such papers, the paper is filled or loaded with mineral pigments, particularly clays, calcium carbonate, talc, titanium dioxide, gypsum, blanc fixe and zinc pigments including lithopone. In addition to their ability to enhance opacity, the fillers improve brightness, printability and smoothness. They may also be used to control ink receptivity to some extent.

The use of fillers for these purposes leads to additional problems for the paper manufacturer. The addition of such non-fibrous materials in substantial proportion makes the paper web Weaker both in wet strength during its formation and in dry strength. To state it simply, filled paper has less strength than equivalent paper containing no filler. It has been estimated, for example, that the use of 10% clay results in about a 20% loss in burst strength and much higher loss in folding endurance.

In the normal operation of the Fourdrinier machine, the stock or furnish containing the mineral pigment filler is fed under acid or alkaline conditions from. a headbox onto the wire where the wet web is formed. Water is drained from the stock first by gravity, then by suction and finally by pressing. The white water removed from the stock is normally recirculated, and it must be recirculated for economy, particularly when pigments are used.

In making filled paper, it is necessary to maintain a sufficient concentration of filler in the headbox to assure that the web retains the desired amount of pigment. This leads to several additional problems. If the retention of ICC filler in the paper web is low, the headbox must have a high concentration of filler. This, in turn, decreases the rate of drainage from the wire and, in general, impedes production. Furthermore, the high filler content in the headbox and its associated circulation systems produce a relatively high rate of erosion and the high rate of filler circulation also decreases wire life.

In addition, when large amounts of filler are being circulated in the white water system, the problem of clari-' fying the white water is compounded. It is necessary to recover the pigments efficiently for economy of operation. Further, the effluents from the white water clarification system require additional treatment to reduce stream pollution. Clarification of white Water is particularly difficult when broke or waste paper which has been sized with an oxidized starch, is used to prepare the furnish, since the oxidized starch has a dispersive action on pigments. This is a serious problem since oxidized starches are commonly used to surface size paper.

It is evident then, that it is highly desirable that the paper web be formed in such manner as to retain as high a proportion of the filler in the stock as possible, for in this Way the amount of filler circulating in the headbox and in the white water can be reduced.

In many of its uses, paper is relied upon because of its structural characteristics. It is required to have burst strength, folding endurance, tensile strength and resistance to tearing. These are in addition to the properties valued for printing or writing such as opacity, brightness, ink receptivity and so on. The structural characteristics of the paper are generally attributed to the continuous, randomly oriented, three-dimensional network of fibers. It is common in making paper to add to the stock any of a wide variety of non-cellulosic polysaccharides in order to improve the paper in various ways. Among such polysaccharides are starch, vegetable gums, cellulose ethers, etc. An almost endless variety of starch products have been used ranging from unmodified starch through the ordinary modified starches such as oxidized and acid-hydrolyzed varieties to starch ethers and esters of almost all known types. See, for example, Cushing and Schumann, TAPPI, vol. 42, 1006 to 1016 (1959) and Swanson, TAPPI, vol. 44, 142A to 181A (1961). Almost any of the varieties of starch increase the burst strength and tensile strength of the paper, but some are better than others. It is thought that starch serves as a crosslinking agent through a hydrogen-bonding mechanism, that is, some sort of cellulose-to-starch-to-cellulose complex is formed to increase the strength of the bonds in the paper. The starch performs this function since it it is in the pasted or highly dispersed form and can therefore achieve contact with the fibers Whereas normally, some individual fibers may not be close enough to form a bond. In a sense, starch serves as an adhesive for this purpose.

In the presence of a substantial proportion of filler, however, starch loses much of its efficacy for this purpose. As noted before, the filler introduces inhomogeneity into the web. It also tends to disrupt the bonds formed between the cellulose and the starch. Of course, it also dilutes the starch. In fact, it has been observed that many varieties of starch that are used to strengthen unfilled papers actually appear to have the reverse eifect in the presence of the filler or they decrease the retention of the 'filler.

In recent years, there have been introduced several derivatives of starch which are designed to increase the retention of filler in pap-er and at the same time to improve the structural properties of filler paper. These starch derivatives are usually ethers that have an anionic group or cationic group, especially a tertiary amino or quaternary ammonium group (see, for example, US. Pats. Nos. 2,935,436; 3,017,294; 3,151,019 and 3,346,563). In general, the starch derivatives having an anionic group are best suited for use with acid furnishes containing substantially no broke sized with oxidized starch. On the other hand, the cationic starches are effective with both acid and alkaline furnishes, with the cationic potato starches being strikingly superior. For example, other things being equal in acid furnishes, quaternary ammonium and tertiary amino ethers of potato starch at pounds per ton of paper are more effective filler retention aids than quaternary ammonium or tertiary amino ethers of corn starch at pounds per ton of paper. In alkaline furnishes, the quaternary ammoium and tertiary amino ethers of potato starch are substantially equivalent to other cationics as retention aids. Since about ninety percent of all paper is produced from acid furnishes, usually containing oxidized starch broke, and since paper producers prefer to employ the same filler retention aid in both acid and alkaline furnishes, it is desirable to provide a corn starch derivative which is at least 75% (preferably in excess of 85%) as effective as cationic potato starches in acid and alkaline furnishes.

The reason or reasons for the greater effectiveness of cationic potato starch in acid furnishes is not readily apparent. While starches from all sources have many similar properties, they differ in particle size, degree of polymerization, amylose content, impurities, paste properties, etc. For example, potato starch has (1) relatively large oval granules in contrast to the smaller frequently polygonal granules of dent corn starch (the most common variety of corn starch), (2) much higher degree of polymerization than corn starch, (3) an amylose content of about 22% as compared to 27% for dent corn starch, (4) no fat or fatty acid impurities while corn starch contains about 1% by weight, (5) covalently bonded phosphorus as opposed to phosphatide impurities in corn starch, etc.

As is well known, the quantity and quality of available potato starch varies not only from crop year to crop year but from mouth to month. Unlike commodity corn, which can be stored from year to year and milled into starch without any serious difiiculties, potatoes deteriorate after relatively short storage periods and become progressively harder to mill into starch. Further, since potatoes are stable foods, only culls, not fit for human consumption, are normally available for conversion into potato starch. On the other hand, commodity corn and other cereal grains have been produced in excess and relatively large supplies are available for milling into starch.

The general object of this invention is to provide starch derivatives having improved filler retention properties in acid furnishes. A further object of this invention is to provide non-potato starches (starch derivatives based on starches other than potato starch) having filler reten tion properties substantially equivalent to cationic potato starch. A further object of this invention is to provide cereal starch derivatives, particularly corn starch derivatives, having filler retention properties substantially equivalent to cationic potato starch in alkaline and acid furnishes. Other objects will appear hereinafter.

We have now found that the objects of our invention can be attained with quaternary ammonium ether nonpotato starches having anionic phosphorus groups bonded covalently to the starch backbone wherein there is a critical ratio of anionic covalent phosphorus to quaternary ammonium groups. For the purpose of this invention, the phrase anionic phosphorus groups bonded covalently to the starch backbone is used in order to differentiate from phosphorus groups bonded ionically to the cationic nitrogen, which anionic groups have no ascertainable effect on the filler retention properties of the starch. In other words, the filler retention properties of the starches of our invention are not enhanced nor diminished by the presence of ionically bonded phosphorus.

The products of this invention have a quaternary ammonium ether D.S. (degree of substitution) of about 0.005 to 1.5, preferably 0.01 to 0.08, and contain from 0.010 to 1.00, preferably 0.010 to 0.50, anionic covalent phosphorous groups per quaternary ammonium ether group. As explained below, the ratio of anionic covalent phosphorus to quaternary ammonium other groups is critical. On the one hand, anionic phosphorus groups bonded covalently to the starch backbone enhance the filler retention properties of cationic starches in acid furnishes. Absent careful control, the filler retention properties of starches containing covalent bonded anionic phosphorus groups in alkaline furnishes are poorer than cationic starches having no anionic phosphorus groups.

The starches of this invention, which can be prepared by reacting starch with a quaternary ammonium etherifying agent and a suitable phosphorus etherifying or esterifying agent can be represented by the structure:

wherein St stands for starch; each R is independently methylene or an alkylene group of 2 to 10 carbon atoms, which may be unsubstituted or substituted with hydroxy groups; R R and R are alkyl groups of 1 to 12 carbon atoms, cyclohexyl, phenyl and benzyl such that, when the three substituents are the same, none has more than 6 carbon atoms, and, when a substituent has more than 6 carbon atoms, the other two are alkyl of up to 2 carbon atoms or R is lower alkyl and R R and the N atoms to which they are bonded form a heterocyclic ring selected from the group consisting of morpholinyl, pyrrolidyl and piperidyl, each having up to one alkyl ring substituent of not more than two carbon atoms; n is a number from 1 to 2; R is alkyl of from 1 to 18 carbon atoms, substituted alkyl of 1 to 18 carbon atoms, alkenyl of 2 to 18 carbon atoms, ROSt, St or M; X is an anionic counter ion and M is a cationic counter ion.

As indicated above, the starch derivatives of this invention contain quaternary ammonium ether groups. Surprisingly, we have found that whereas the quaternary ammonium ethers of non-potato starch containing from about 0.01 to 1.00 anionic covalent phosphorus groups per quaternary ammonium ether group are at least 75 as effective in filler retention as a standard cationic potato starch, the tertiary amino ethers of non-potato starch containing from 0.06 to 0.42 anionic covalent phosphorus groups per tertiary amino ether group include derivatives that are (a) approximately equivalent to the standard in alkaline furnishes but less than 70% as effective in acid furnishes and (b) approximately equivalent to the standard in acid furnishes but less than 60% as effective in alkaline furnishes. For example, a tertiary amino ether of corn starch (D.S. 0.038) containing (a) 0.06 anionic covalent groups per cationic group is fully equivalent to the standard in alkaline furnishes and about 66% as effective as the standard in acid furnishes, (b) 0.15 anionic covalent groups per cationic group is fully equavalent to the standard in alkaline furnishes and about 94% as effective as the standard in acid furnishes, (c) 0.24 anionic covalent groups per cationic group is about 95% as effective as the standard in acid furnishes and about 79% as effective as the standard in alkaline furnishes and (d) 0.42 anionic covalent groups per cationic group is fully equivalent to the standard in acid furnishes and about 59% as effective as the standard in alkaline furnishes. On the other hand,

a quaternary ammonium ether of corn starch (D.S. 0.0335) containing (a) 0.0 14 anionic covalent groups per cationic group is fully equivalent to the standard in alkaline furnishes and about 87% as effective as the standard in acid furnishes, (b) 0.16 anionic covalent groups per cationic group is fully equivalent to the standard in both acid and alkaline furnishes, (c) 0.43 anionic covalent groups per cationic group is fully equivalent to the standard in acid furnishes and about 94% as effective as the standard in alkaline furnishes and (d) 0.92 anionic covalent groups per cationic groups is fully equivalent to the standard in acid furnishes and about 77% as effective as the standard in alkaline furnishes.

Accordingly, it is possible to prepare quaternary ammonium nonpotato starch ethers that are at least 85% as effective as the standard in both alkaline and acid furnishes over the preferred range of 0.01 to 0.50' anionic groups per cationic group. On the other hand the tertiary amino ethers are only this effective over an extremely small range which makes it extremely difficult to consistently produce products industrially having the desired effectiveness.

Briefly, the cationic-anionic starches of this invention are prepared by reacting starch with a quaternary ammonium etherifying agent and a suitable phosphorus etherifying or esterifying agent.

Suitable non-potato starches useful in this invention include dent corn starch, wheat starch, sorghum starch, rice starch, waxy maize, high-amylose corn starch, such as those containing from about 50 to 80% by weight amylose, waxy sorghum, cassava starch and the amylose and amylopectin fractions thereof. These starches may be modified by enzyme treatment or by hydrolysis with an acid, for example, or derivatized with monofunctional reagents, such as ethylene oxide, propylene oxide, acetic anhydride, vinyl acetate, etc. The preferred starches are the readily available common variety uninhibited cereal starches, such as dent corn starch, wheat starch, rice starch and sorghum starch. Of these, commodity dent corn starch is particularly preferred.

The quaternary ammonium etherifying agents useful in this invention include any of those disclosed in US. Pat. 2,876,217 and US. Pat. No. 3,346,563, all of which disclosures are incorporated herein by reference. Broadly speaking, these reagents belong to three classes which are: (1) omega-haloalkyl ammonium compounds; such as 2- bromoethyl trimethyl ammonium chloride, l-bromomethyl triethyl ammonium bromide, 2-iodoethyl triethyl ammonium chloride, etc.; (2) vicinal-epoxyalkyl ammonium compounds, such as 2,3-epoxypropyl trimethyl ammonium chloride, 3,4-epoxybutyl triethyl ammonium bromide, 2,3- epoxybutyl methyldiethyl ammonium iodide, etc; and (3) vicinal-halohydroxyalkyl quaternary ammonium compounds, such as 2,3-chlorohydroxypropyl trimethyl ammonium chloride, 2,3-chlorohydroxypropyl triethyl ammonium chloride, etc.

The various quaternary ammonium etherifying agents can be used in a mole ratio of about 0.007 to 4 moles per mole starch. However, the optimum concentration of each etherifying agent is dependent in part on the efficiency of the reagent and the desired D.S. (degree of substitution). Although the non-potato starch can have a quaternary ammonium D.S. of about 0.005 to 1.5, it is economically desirable, and hence preferred, to provide products having a D5. of about 0.01 to 0.08. Above D.S. 0.08, the filler retention properties are not improved suf ficiently to justify the additional cost of reagent and problems associated with increased water-sensitivity of the starch product produced in slurry reactions. Lower D.S. products are also preferred, since many paper producers rely on cationic starches to improve paper strength (Mullen value). At higher D.S. difficulty is experienced adding sufficient cationic starch to impart the desired Mullen value without flocculating the furnish.

The reagents suitable for bonding anionic phosphorus groups to starch include alkali metal and alkaline earth metal salts of phosphoric acid, such as those described in US. Pat. 3,132,066 which disclosure is incorporated by reference, and phosphonate etherifying agents which are the subject of commonly assigned application Ser. No. 694,056 filed on even date, which disclosure is incorporated by reference, wherein the organo group bonded directly to the phosphorus atom of the phosphonate etherifying agent is an omega-haloalkane, a vicinal halohydroxyalkane, a vicinal epoxyalkane or a vinyl group. Suitable phosphonating agents include (1) vinylphosphonates such as diethyl vinylphosphonate, dichloroethyl vinylphosphonate, etc.; (2) vicinal halohydroxyalkanephosphonates, such as 1-chloro-2-hydroxyethanephosphonic acid, Z-chloro-1-hydroxyethanephosphonic acid, 2- bromo-3-hydroxypropanephosphonic acid, methyl hydrogen 2 chloro-3-hydroxypropanephosphonate, di(N,N- diethylaminoethyl) 2 chloro 3 hydroxypropane phosphonate, diglycidyl 3 chloro 4 hydroxybutanephosphonate, etc.; (3) vicinal epoxyalkanephosphonates, such as epoxyethanephosphonic acid, 2,3-epoxypropanephosphonic acid, diethyl 2,3-epoxypropanephosphonate, 3,4- epoxybutanephosphonic acid, etc. and (4) omega-haloalkanephosphonates such as chloromethanephosphonic acid, dimethyl bromomethanephosphonate, 3 bromopropanephosphonic acid, etc. The vicinal halohydroxyalkanephosphonates are new compounds and the subject 3f copending application Ser. No. 694,091 filed on even ate.

The starch products formed by reacting the aforesaid etherifying and esterifying agents contain anionic groups. Even under mild reaction conditions approximately half of the diester groups of the phosphonating agents are converted to the free acid or salt form and/or take part in transesterification reaction with starch hydroxyl groups. For optimum filler retention, it may be desirable to acid hydrolyze the products prepared with phosphonate diesters in order to reduce or eliminate any cross-linkages formed. The various phosphorus containing etherifying and esterifying reagents can be used at a mole ratio of 0.0001 to 4 moles per mole starch. However, the optimum concentration of each reagent is dependent in part on the efficiency of the reagent in combining covalently with starch and the concentration of quaternary nitrogen in the final product.

In accordance with this invention, the starch etherifying or esterifying catalysts include sodium hydroxide, potassium hydroxide, calcium hydroxide, barium hydroxide, sodium carbonate, disodium phosphate, sodium aluminate, tetramethyl ammonium hydroxide, etc. The above compounds are representative of the alkali metal hydroxides, alkali metal salts of weak acids, quaternary ammonium hydroxides, and alkaline earth metal hydroxides.

The starch products of this invention can be prepared by reacting starch with first one class of reagent and then the other. Both routes have advantages and disadvantages. For example, if the starch is reacted first with the quaternary ammonium etherifying agent followed by the anionic phosphorus reagent, extreme care must be taken in making certain that the final product contains the necessary concentration of anionic covalent phosphorus. Care is necessary since the product will also contain anionic phosphorus bonded ionically to the quaternary nitrogen. Phosphorus, which is not bonded covalently, has no ascertainable effect on the filler retention properties of the star-ch. This problem is minimized by reacting starch first with the phosphorus containing reagent. However, the anionic phosphorus containing starch ethers and esters have more of a tendency to swell during the subsequent quaternary ammonium etherifying reaction which is preferably carried out in a slurry reaction.

The preferred method of etherifying starch with either quaternary ammonium etherifying agent or phosphonate etherifying agent comprises suspending granular starch in a polar solvent, preferably water, in such a manner that the starch comprises from about 2 to 60% by weight of the composition followed by adding an alkaline catalyst. Alternatively, the granular starch may be suspended in a polar solvent containing the alkaline catalyst. The etherification reaction is then carried out at a pH of from about 9 to 13 with sufficient alkali to establish the pH. The reaction proceeds rapidly at moderate temperature and, in some cases, may require external cooling to prevent gelatinization of the starch derivative where a granular product is desired.

Temperature of the etherification reaction may be as low as 10 C. or as high as 200 C. As a rule, reaction time varies inversely with reaction temperature. For example, the ether can be prepared by heating starch, reagent, alkaline catalyst and a suitable plasticizer, e.g. water, under conditions of severe working as in a plastics extruder as disclosed in U.S. Pat. 3,137,592, filed Apr. 3, 1961. With this method, the reaction temperature can range from 150200 C. and the reaction time, i.e. the extruder retention time, can be as short as 1 to 2 minutes. Much lower temperatures are required if the starch ether is to be recovered in original granule form from water as reaction medium. To avoid undesirable swelling of the starch granules during such etherification, the reaction temperature is preferably kept below the swelling or gelatinization temperature of the original starch. Thus 40-75 C. is a satisfactory reaction temperature range for the preparation of ungelatinized ethers of common corn starch by water slurry reaction. Reaction temperatures up to 100 C. may be advantageously used in aqueous paste etherifications or in original granule etherifications when the reaction medium is chosen to suppress gelatinization or swelling. Examples of reaction media which inhibit starch granule swelling are water solutions of selected inorganic salts, e.g. sodium chloride, sodium sulfate, sodium carbonate, magnesium sulfate, and organic liquids, e.g. lower alcohols and dioxane.

As indicated above, the proportion of reaction medium for the etherification reactions can vary widely. In the extruder method, for example, water may be the reaction medium and plasticizer, at a proportion of 25 parts by weight, for example, per 100 parts by weight of dry substance starch. In the preparation of ungelatinized ethers by slurry reaction, the proportion of reaction medium (e.g. water, aqueous salt solution, lower alcohol) may be as small as 125 mls. per 100 gms. of starch but preferably will be larger, e.g. 200 mls. per 100 gins. of starch. Still larger proportions of reaction medium, e.g. 10 to 20 mls. per gram of starch, may be required in the paste etherifications because of viscosity effects. Although water is the preferred medium for paste etherification, other liquids, e.g. dimethylsulfoxide, may be used.

The etherification reaction may also be performed on granular starch in the superficially dry condition. For example, ungelatinized starch containing 20% moisture may be tumbled and heated to yield an ungelatinized starch ether. Generally more than 10% water is required.

The preferred method of phosphating starch comprises forming an aqueous starch slurry at room temperature and adding thereto a suitable concentration of phosphate. The pH of the starch slurry is then adjusted to about 4 to 11.5 using one of the aforesaid alkaline catalysts and/ or acids such as acetic acid, hydrochloric acid, sulfuric acid, etc. Preferably, the pH is adjusted to between 4 and 6 in order to minimize the formation of cross-linkages. The composition is then filtered without washing.

The starch composition is then adjusted to a moisture level of about 20% or below, preferably from about to 20% by weight at a temperature of less than about 70 C. in order to avoid undesired swelling or pasting of the starch where a granular starch product is desired. The starch-phosphate composition is then roasted at a temperature of 100 to 160 C., preferably 120 to 140 C.

until the product has the desired level of anionic phosphate groups.

The starch derivatives of this invention are added to an aqueous pulp suspension or paper stock, as in the beater of a paper making system or at any point prior to web formation in a concentration of about 0.001 to 1% by weight of the dry pulp. When added in the proper concentraiion, the starch derivatives are effective in improving filler retention and dry strength of the resultant paper over the entire pH range of about 4 to 10, which is normally employed for making paper.

Suitable fillers for use in this invention include clay, titanium dioxide, calcium carbonate, magnesium carbonate, talc, calcium sulfate, etc.

Example I A 3-(N,N,N-trimethylammonium chloride)-2-hydroxy propyl granular corn starch derivative was prepared by adding 295 parts by Weight of an aqueous vicinal 2,3- chlorohydroxypropyl trimethylammonium chloride composition, prepared in the manner described in Example 1 of U.S. Pat. 3,346,563 containing 59 parts dry weight active vicinal 2,3-chlorohydroxypropyl trimethylammonium chloride, to 1000 parts by weight granular corn starch (dry solids basis) suspended in 1000 parts by Weight water and reacting the components for sixteen hours at a temperautre of about F. and at a pH of about 11, established with sodium hydroxide. The granular starch slurry was neutralized with sulfuric acid, washed and dried, yielding the desired quaternary ammonium ether having a D8. of 0.036.

Eleven hundred parts by weight of 3-(N,N,N-trimethylammonium chloride)-2-hydroxypropyl granular corn starch prepared in the manner described above was slurried in 1100 parts by weight water containing 14.4 parts by weight disodium hydrogen phosphate and 81.4 parts by Weight sodium dihydrogen phosphate monohydrate, adjusted to pH 5.6, stirred for twenty minutes, filtered and air dried without washing. Two hundred parts by Weight portions Were roasted at 145 C. for respectively (a) 30 minutes, (b) 45 minutes, (0) 60 minutes, and (d) minutes. Carefully washed samples had covalent phosphate D.S. of (a) .0033, (b) .0066, (c) .0118 and (d) .0254 and had (a) .092, (b) .183, (c) .33 and (d) .71 covalent anionic phosphorus groups per cationic nitrogen group.

The above starches and the parent unmodified starch were compared with a commercially available cationic potato starch as filler-retention aids in a standardized lab oratory test in hand made sheets of paper. The starches were pasted in hot water (9395 C.) at 1% solids for 30 minutes accompanied by uniform moderate stirring. The paper furnish contained 90 parts by Weight bleached sulfite fiber (690 ml. S.R. freeness), 10 parts by weight titanium dioxide, 1.0 part by Weight of cooked oxidized starch and 0.25 part by weight of the starch being tested. Both acid and alkaline hand sheets Were made. In the acid sheets, the pH of the furnish was adjusted to 5.0 to 5.5 pH with dilute hydrochloric acid and 2 parts by weight of alum and 2 parts by weight rosin were added. In the alkaline sheets, the pH was controlled at 8.0 to 8.5 by the addition of dilute hydrochloric acid. Weighed portions of the dry hand sheets were ashed by standard procedure to determine total ash content and from this value, after correction for ash in an unfilled sheet, the percent of original filler retained by the paper. The results listed below are an average of triplicate sets of hand tion ratio was 80.0/75.1 or 1.06 while the alkaline filler sheets: retention ratio was 71.9/ 76.1 or 0.94.

TABLE I Number of covalent anionic phosphate groups per cationic nitrogen Acid filler Alkaline filler Starch employed group retention ratio 1 retention ratio 1 gnmgdified granular corn starch 422/869 or 0.49.- 21.2/66.1 or 0.32.

tare

0.092 732/869 or 0.85.. 75.7/66.1 or 1.15. 0.183 87.7/86.9 or 1.01" 70.3/66.1 or 1.06. 33 903/869 or 1.04.. 68.0/66.1 or 1.03.

0. 0. 71 931/869 or 1.07- 503/661 or 0.77.

1 Percent filler retention of starch tested divided by percent filler retention of cationic Eleven hundred parts by weight of a 3-(N,N,N-tri methylammonium chloride)-2-hydroxypropyl granular corn starch having a D8. of .0335, prepared in the manner described in Example I, was slurried in 1100 parts by weight water containing 14.4 parts by weight disodium hydrogen phosphate and 81.4 parts by weight sodium dihydrogen phosphate monohydrate, adjusted to pH 5.6, stirred for 20 minutes, filtered and air dried without Washing. Two hundred parts by weight portions were roasted at 145 C. for respectively (a) minutes, (b) 30 minutes, (c) 60 minutes and (d) 120 minutes. Carefully washed samples had covalent phosphate D.S. of (a) .00046, (b) .0052, (c) .0146 and (d) .031 and had (a) .014, (b) .16, (c) .43 and (d) .92 covalent anionic phosphorus groups per cationic nitrogen group. The above starches were compared with a commercially available cationic potato starch as filler-retention aids in the manner described in Example I. The results listed below are an average of triplicate sets of the hand sheets:

Example IV This example illustrates the preparation of quaternary ammonium starch ether phosphonate. One thousand nine hundred and fifty-five parts by weight granular corn starch was suspended in 3,920 parts by Weight Water. Fifty-seven and two tenths parts by weight diethyl vicinal chlorohydroxyethane phosphate prepared in the manner described in Example I of applicationSer. No. 694,091 filed on even date was added to the starch slurry. Over a period of six hours 47.86 parts by weight dry calcium hydroxide was added while maintaining the pH of the reaction mass at 11 and at between 43 to 49 C. The granular starch ether phosphonate half-ethyl ester having a phosphonate D.S. of 0.0047 was carefully washed and dried.

Twenty-seven and seventy-five hundreds parts by weight of the starch ether phosphonate half-ethyl ester was suspended in parts by weight water containing one part by weight calcium hydroxide. Six tenths part by Weight 2,3- epoxypropyl trimethylammonium chloride was then added to the reaction mass, which was stirred at 40 C.

TABLE II Number of covalent anionic phosphate groups per cationic nitrogen Acid filler Alkaline filler Starch employed group retention ratio 1 retention ratio 1 0. 014 72.5/83.7 or 0.87.- 77.8/76.1 or 1.02. 0.16 84.0/83.7 or 1.00.. 77.0/76.1 or 1.01. 0. 43 85.3/83.7 or 1.02 71.1/76.1 or 0.94. 0.92 82.6/83.7 or 0.99 58.3/76.1 or 0.77.

Percent filler retention of starch tested divided by percent filler retention of cationic potato starch standard.

Example III This example illustrates the preparation of a granular corn starch wherein the starch is reacted first with the phosphating agent followed by the quaternary ammonium derivatizing agent. Five hundred parts by weight corn starch (11.6% by weight water) was suspended in 500 parts by Weight water containing 17.6 parts by weight disodium hydrogen phosphate and 25.6 parts sodium dihydrogen phosphate monohydrate, and adjusted to pH 5.3. The slurry was stirred for 20 minutes and then filtered and dried without washing. The superficially dry composition was then roasted at 145 C. for 70 minutes. The resultant starch phosphate had a covalent anionic phosphorus D8. of 0.021.

Two hundred and forty parts by weight of the starch phosphate prepared in the preceding paragraph was suspended in 425 parts by weight 3A ethanol and 100 parts by weight water. Fifty parts by weight of crystalline 3- chloro-2-hydroxypropyl trimethylammonium chloride was added followed by 25 mls. of 50% by weight aqueous sodium hydroxide. The reaction mass was stirred at between 35 and C. for four hours, filtered, washed carefully and dried. The resultant product had a quaternary ammonium ether D8. of .103 and contained .20 covalent anionic phosphorus groups per cationic nitrogen group. The starch product was evaluated for filler retention in the manner described in Example I. The acid filler retenfor 18 hours. The resultant product was carefully washed, filtered and dried. The cationic starch ether phosphonate had a quaternary ammonium D8. of 0.0187 and 0.25 anionic phosphorus groups per cationic nitrogen group.

Acid hand sheets were prepared from the starch ether phosphonate half-ethyl ester of paragraph 1 and the quaternary ammonium ether of said starch ether phosphonate half-ethyl ester of paragraph 2 in the manner described in Example I. The starch ether phosphonate half-ethyl ester retained 57.8% of the ash while the quaternary ammonium ether starch ether phosphonate half-ethyl ester retained 67.6% by weight ash.

Since many embodiments of this invention may 'be made and since many changes may be made in the embodiments described, the foregoing is to be interpreted as illustrative only and our invention is defined by the claims appended hereafter.

What is claimed is:

1. A quaternary ammonium ether non-potato starch bearing covalent anionic phosphorus groups selected from the group consisting of phosphate and ether phosphonate wherein said starch has a quaternary ammonium ether D.S. of about 0.005 to 1.5 and contains from about 0.010 to 1.00 covalent anionic phosphorus groups per quaternary ammonium ether group.

2. The quaternary ammonium ether non-potato starch of claim 1, wherein said starch is a cereal starch.

3. The quaternary ammonium ether non-potato-starch of claim 2, wherein said starch has a quaternary ammonium ether D5. of about 0.01 to 0.08 and contains from 0.010 to 0.50 covalent anionic phosphorus groups per quaternary ammonium ether group.

4. The quaternary ammonium ether non-potato starch of claim 2, wherein said cereal starch is com starch having a quaternary ammonium ether D8. of about 0.01 to 0.08 and contains from 0.010 to 0.50 covalent anionic phosphorus groups per quaternary ammonium ether group.

5. The quaternary ammonium ether non-potato starch of claim 4, wherein said quaternary ammonium ether group is a 3-N,N,N-trimethylammonium-Z-hydroxypropyl ether salt.

6. A paper containing dispersed throughout the cellulosic fibers thereof, a quaternary ammonium ether nonpotato starch in an amount effective for filler retention and dry strength, said starch bearing covalent anionic phosphorus groups selected from the group consisting of phosphate and ether phosphonate wherein said non-potato starch has a quaternary ammonium ether D5. of about 0.005 to 1.5 and contains from about 0.010 to 1.00 covalent anionic phosphorus groups per quaternary ammonium ether group.

7. The paper of claim 6, wherein said non-potato starch is corn starch having a quaternary ammonium ether D8. of about 0.01 to 0.08 and contains from 0.010 to 0.50 covalent anionic phosphorus groups per quaternary ammonium ether group.

8. In the method for making paper utilizing a wire on which to form a wet web, the improvement comprising the step of adding a quaternary ammonium ether nonpotato starch in an amount effective for filler retention and dry strength, said starch bearing covalent anionic phosphorus groups to paper stock, at any stage prior to passing the stock onto the Wire, wherein said starch has a quaternary ammonium ether D8. of about 0.005 to 1.5, said anionic phosphorus groups are selected from the group consisting of phosphate and ether phosphonate and said starch contains from about 0.010 to 1.00 covalent phosphorus groups per quaternary ammonium ether group.

9. The method of claim 8, wherein said starch is corn starch having a quaternary ammonium ether D8. of about 0.01 to 0.08 and contains from 0.010 to 0.50 covalent anionic phosphorus groups per quaternary ammonium ether group.

References Cited UNITED STATES PATENTS 3,132,066 5/1964 Kerr et a1 162175 3,448,101 6/1969 Billy et al. 162175X 3,459,632 8/1969 Caldwell et al. 162-175 S. LEON BASHORE, Primary Examiner F. FREI, Assistant Examiner U.S. Cl. X.R.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Dated February 1 Patent No. 2, 103

Inventor(s) Kenneth B. Moser and Frank Verbanac It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 10, line 23, for "phosphate" read ---phosphonate-- Signed and sealed this 10th day of August 1971.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. WILLIAM E. SCHUYLER, JR.

Commissioner of Patents Attesting Officer USCOMM-DC 5031 

